#app {
    position: relative;
    width: 1000px;
    margin: 0 auto;

    .img-wrap {
        width: 904px;
        height: 408px;
        // border: 2px solid black;
        box-sizing: border-box;
        margin: 0 auto;

        ul {
            li {
                float: left;

                img {
                    width: 300px;
                    height: 200px;
                }
            }
        }
    }

    .big {
        display: none;

        .img-big {
            width: 904px;
            height: 408px;
            //  border: 2px solid black;
            margin: 0 auto;
            background-color: #fff;
            opacity: 0.7;
            position: absolute;
            top: 0px;
            left: 50px;

        }

        .big-img {
            img {
                width: 500px;
                height: 300px;
                position: absolute;
                top: 50px;
                left: 250px;


            }

            span {
                width: 20px;
                height: 20px;
                background-color: red;
                display: block;
                text-align: center;
                line-height: 20px;
                position: absolute;
                top: 50px;
                right: 230px;
                cursor: pointer;
            }

        }
    }

}